Hey, I am sorry, I didn’t realize you’re in a hurry initially. 
I have added your email to the testers list (PM me if the one you’re using for Android Play Store is different from the one you’re using here)
Please follow the instructions to install here: https://blokas.io/pisound/docs/pisound-app/#android
An alternative way could be to use the button and swapping the USB memory sticks, or switch patches based on the number of the button clicks, as @oootini demonstrated here: Adding more button clicks